1. Field of the Invention
An adaptor is described for replacing the filter in a fuel line. The adaptor has a quick release and attachment means for a pressure gauge. This adapter simplifies and expedites troubleshooting, particularly in vehicles that are equipped with throttle body fuel injection systems.
2. Description of the Prior Art
In the early 1980's about 6% of the cars manufactured in the United States were equipped with fuel injection systems. By 1989 about 96% of the cars manufactured in the United States were equipped with some type of fuel injection system. These systems are divided into two popular types; one is called port injection and the other is called central point or throttle body injection (TBI).
In port fuel injection systems the fuel is injected directly into the intake manifold near the cylinder intake valves where the fuel is mixed with air. The system usually has a provision whereby a pressure gauge can be attached to the fuel lines to measure the pressure.
In the TBI injection systems the fuel is injected into a central chamber where the fuel is mixed with air. The fuel air mixture is then drawn into the cylinder through the intake manifold, as was done previously using a carburetor. Most TBI fuel injection systems do not have a provision for attaching a gauge to the fuel lines for pressure measurement. The majority of the automobiles manufactured by General Motors (GM), for example, have the TBI type of injection which, at this point in time, numbers about 20 million automobiles.
One persistent problem with the GM TBI is the occasional sluggishness and delayed reaction felt when the engine is accelerating under load. This common symptom results from a loss of fuel pressure, which would be indicative of a need for replacing the fuel pump, replacing a bad or clogged fuel filter, or that a tune up is necessary. The current procedures for checking the fuel pressure in the TBI systems are cumbersome and time consuming. Checking the fuel pump on GM TBI fuel systems, for example, is imprecise in determining the cause for sluggishness and delayed acceleration. The steps currently in use to test these fuel systems are:
1. Remove the fuel pump fuse from the fuse block and crank engine. PA1 2. Run the engine until it stalls when the fuel in the system runs out. PA1 3. When the engine dies, crank the engine for approximately 3 seconds to insure that all the fuel is evacuated from the fuel lines. PA1 4. Turn the ignition off and reinstall the fuel pump fuse. PA1 5. Remove the air cleaner and plug the thermostatic air cleaner vacuum port on the throttle body unit. PA1 6. Remove the steel fuel line between the throttle body and the fuel inlet line. PA1 7. Install a fuel pressure gauge between the throttle body unit and the fuel inlet line. PA1 8. Start the engine and observe the fuel pressure reading. PA1 9. De-pressurize the fuel system as described in steps 1-4. PA1 10. Remove the fuel pressure gauge and re-install the steel line to the throttle body. PA1 11. Start the car and watch for fuel leaks. PA1 12. Remove the plug from the throttle body vacuum port and re-install the air cleaner.
This whole procedure requires at least 40 minutes to perform. Fuel pressure readings cannot be taken when the engine is accelerating under load such as under normal driving conditions or on a dynamometer.
There are many pressure testing devices described in the literature and on the market. U.S. Pat. No. 2,566,742 issued 1 Sep. 1951 to C. A. Odell, describes a device for measuring the amount of fuel used and the pressure of the fuel. The gauge is an intricate part of the testing apparatus and cannot be detached for other types of pressure testing. U.S. Pat. No. 4,534,224 issued 13 Aug. 1985 to S. G. Raftis, describes a fuel pressure testing device wherein the gauge is connected to the fuel system through a diaphragm which prevents the pressurized fluid from coming into contact with the tubing of the pressure gauge. The gauge is fixed to the unit. U.S. Pat. No. 3,869,905 issued 11 Mar. 1975 to M. T. Allen, provides a method for testing oil pressure in a gasoline or diesel engine. This unit is used to isolate the oil pump assembly from the engine's lubricating system to determine which of the two systems is responsible for an oil pressure problem. U.S. Pat. No. 2,351,027 issued 13 Jun. 1944 to W. M. Ewart et al, describes a device for measuring the fuel flow in a carburetted engine system. U.S. Pat. No. 3,292,428 issued 20 Dec. 1966 to D. M. Motl, describes a device to test the pressure of a fuel pump. U.S. Pat. No. 2,333,252 issued 2 Nov. 1943 to B. M. Ikert, is drawn to a fuel line testing device that measures both fuel flow and fuel pressure. U.S. Pat. No. 2,803,961 issued 27 Aug. 1957 to J. Z. Harmon, describes a device for testing and clearing oil lines. This device has a gauge that is attached to a cylinder through an opening. These and other testing units, such as U.S. Pat. No. 2,859,612 issued 11 Nov. 1958 to H. H. Morse, do not have the flexible connection to the gauge nor do they have any indication that they can be substituted for the fuel filter in a TBI fuel system. None of the above references teach the replacement of the fuel filter, in a fuel line, with an adaptor device to which a standard fuel pressure gauge can be attached by a flexible tubing, to measure the pressure of the fuel within-the line.
It is the object of this invention to provide an adaptor that can be used to measure the fuel pressure in a fuel injected automobile engine. The adaptor can be placed in the fuel line or substituted for the fuel filter normally provided in the fuel inlet to filter the fuel line before it reaches the injector.
It is a further object of this invention to provide a means for measuring the fuel pressure in a fuel injected engine by providing an adapter that can be inserted in place of the fuel filter in the pressurized line.
It is a yet further object of this invention to provide an adapter that is placed in the pressurized line of a fuel injected engine that will measure the fuel pressure while the engine is under load.
A still further object of this invention is to provide a means for quickly testing the pressure of a pressurized fuel line that has no provisions for checking the pressure.